Process for treating ferrous metal to prevent corrosion



' April 13 1926. 1,580,647

G. D. BRECK PROCESS FOR TREATING FERROUS METAL TO PREVENT CORROSIONFiled Feb. 25, 1921 Patented Apr. 13, 1926 UNITED STATES GEORGE. D.BRECK, OF CLEVELAND, OHIO.

PROCESS I FOR TREATING FERROUS METAL TO PREVENT CORROSION.

Application filed February 25, 1921. Serial No; 447,772.

To all whom it may concern: I

Be it known that I, GEORGE D. BRECK, a citizen of the United States,residing" at Cleveland, in the county of Cuyahoga and 5 State of Ohio,have invented a certain new and useful Improvement in Processes forTreating Ferrous Metal to Prevent Corrosion, of which the following is afull, clear, and exact description, reference' beinghad to theaccompanying drawings. This invention relates to the treatment offerrous metal for the purpose of preventing corrosion. The fundamentalobject is the provision of a tube or pipe so treated, either-internallyor externally or both, as to be usable for the economizers of steamboilers, or feed water heaters, since it is well known that ordinarysteel pipes become corroded very rapidly when put to this use,

interiorly .because of the air, gas, or chemical substances dissolved inthe water, and exteriorly because of the acid deposit con-. densedthereon from the furnace gases, or surrounding atmosphere. However myinvention is not limited to this use inasmuch as a tube which hassufiicient resistance to corrosion for the purpose indicated is alsousable in numberless other relations in the arts, and a process whichwill produce such a tube is equally applicable to the-production offerrous metal articles for a great variety of different technicalpurposes,

whether subjected to hot, cold, wet, dry,

acid, alkaline, climatic or other injurious conditions; and I herebydeclare my purpose to claim and secure my invention for all uses towhich the same maybe applicable.

Subsidiary objects of the invention are the provision of a method oftreating ferrous metal which is applicable to commercial, hot-rolled orforged, steel products and of all manner of cross section; which can beemployed without departing from th established commercial methodsofsteel rolling; which is applicable to steel in the duetile state andis not restrictedto castings as in the case of many non-corrodiblecompositions heretofore suggested; which does not materially decreasethe flexibility or duetility or other physical properties of the material; which can be performed with commercial and inexpensivematerials; the pros vision of certain new and improved articles and comositions of matter; while other ob jects an advantages of. the inventionwill become apparent as the description proceeds. The essence of myinvention resides in'the superficial application to a ferrous metalwhile rendered plastic by heat, of a protective metal or alloy in finelydivided form, and immediately incorporating the a same' into the ferrousmetal by'mechanical working such as rolling or forging, the temperatureof the ferrous metal being below the melting point of the addedmaterial. I do not restrict myself to the use of any one metal or alloyexcepting that the applied material inust be one which will alloy withthe ferrous metal with the production of a solid solution alloy' forminga coating which is highly resistant to corrosion and is so closelyadherent as not to scale or peel oif; and further that it should possessa 'sufliciently high melting point to withstand all ordinaryvicissitudes of use. These considerations alone exclude the employmentofmaterial consisting of or containing any large proportion of suchingredients as tin,

lead, zinc, arsenic,,antimony, bismuth, cadmium, or the like lowmelting-point metals. The material which I specially prefer is chromiumor an alloy thereof, such as ferrochrome, or a mechanical'mixture offinely divided chrominum and iron; silicon also can be used to"advantage in many cases, especially in association with other materialssuch as iron, chromium or aluminum. All these materials arecharacterized by the production of an impervious, adherent, insolublealloy. Thus a commercial ferrochrome containing a rather largepercentage of silicon. affords the desired chemical advantages togetherwith the physical property of being not unduly difficult to pulveriz e.Also the mixture of finely divided iron and chromium which is producedwhen chromite ore is reduced at temperatures' below the melting point ofiron or chromium, forms a very convenient material.

-This -1naterial, mixed if desired with a suitable fiuxing compound, issprinkled on the surface ofthe white-hot blank, slab or billet justpriorto its passing through the rolling mill, whereupon the pressure causes atrue alloying-of the ingredients even though the temperature be notsufliciently high to produce true fusion of the applied materials. Infact it' is better not to have fusion of these materials sincewithfusion they become mobile and tend to segregate into drops and areremoved by the rolling or forging operations Whereas if fusion isavoided they remain in place. Before applying this treatment Ipreferably roll or forge the metal sufiiciently toward its finisheddimensions so that the sulisequ'ent operations shall .not serve todestroy the applied coa'ting, reheating if necessary just prior toapplying the powdered'or .granuiar material. Also the nature of theoperation first performed after such application .is'

preferably one which does not greatly change the shape ofthe metalsection but opposite side and immediately re-roll the faces; Fig. 7

only incorporates the added material intimately therewith, although thisis generally 'altended with a decrease in the thickness of the blankaccompanied by a corresponding spreading. After the coating isthus'fixed in place the article can be repeatedly rolled or forged, thesurface layers expanding with the body parts throughout a considerablerange of manipulation. Thus for example the blank may be circled intothe form of a tube, having the coating either inside or outside,-or maybe rolled into an I beam or other desired cross-section. In case it bedesired to coat both sides 1 effect this byinverting the billetimmediately after it has passed through the first rolls, apply a s1m1-lar coatmg of powdered ,materi'al upon its same, the smallest possibletime being permitted to elapse between the two treatments so as to avoidunnecessary cooling.

In the drawings accompanying and forming part of this ap lication Fig. 11s a perspective viewshowing diagrammatically the performance of myinventiom'Figs. 2 3, and

4 illustrate the simultaneous extension of both coating and body uponworking; Fig. 5 is a cross-sectional View of a tube having the describedcoating on its outer surface; Fig. (5 is a cross-sectional view ofablank having the described coating on both surillustrates a tube,having the described coating on both surfaces; and F 1g. 8 is a crosssectional view of an I beam treated as herein described.

-'same is 'cirel'ed and subse Describing the drawings by referencecharacters, 1 represents a white-hot,steel or iron, sheet or'billet, and2 -2 the rolls between which the same is passed, same bein of anymaterial known and used for tl at purpose, such as chilled cast 1ron, '3represents the coating of applied pulverized materi'al prior to therolling and 4 represents a mechanical device of any suitable typeadapted to shower the materialupon theentire surface of the metal in auniform layer of the desired thickness. 5 illustrats'the body and 6 thecoating ofthe'resulting sheet or plate. \Vhen made into tube form thewelded iin the usual Imanner-a ong the flougitudinal'line 77. In case ofa-hot'rolle'd 'uently seam tube the coating can be applied during therolling process and a seamless tube secured with the ncn corrodiblesurface I have decles are useful not only' in connection withboilcrs andtheir accessories, but also in bridges and structural works exposed toclimatic rusting; to furnaces, stove parts, and metallurgical appliancesexposed to high temperature corrosion; to various purposes scribed.- 8indicates a preheating device such as .a as burner which may be used ifdesired. y improved compound metal artiwhere chemical corrosion isencountered;

and in numerous other situations.

It will be understood that I do not restrict myself to the operation ofrolling as the sole means of incorporating the powdered ingredientswiththe ferrous metal but have merely illustrated this as a type of,

mechanical working which involves pressure and which can also berelieved by such other steps as forgmg or hammering; also that I donotrestrict myself-t0 steel, since wrought iron, charcoal iron, andother Varieties of ferrous metal can be treated in this way, and alsosuch special alloys as nickel, steel, vanadium steel, and the like; I donot restrict myself to any particular degree of fineness of the appliedcoating, nor to any shape of finished article, and generally that I donot restrict myself in anywise except as specify cially set forth in theannexed claims.

,Having thus described my invention what I claim is:

1. The process of producing non-corrodible meta steps of heating a slabor sheet of ferrous 'metal to a high temperature short of melt ing,covering the [same with a superficial coating of a finely dividedmetallic subelements which contains the containing finely dividedmetallic chromium i or an alloy thereof, incorporating such,

coating into such slab or blank by mechanical pressure, and subsequentlyreducing the slab. or blank to finished form by repeated rollingoperations.

3. The vprocessof treating ferrous metal to prevent corrosion whichcontains the step of rolling pulverized 'ferro chrome 'into the surfacethereof at whiteheat. I v

4. he process of rendering steel incorrodible which contains the-stepof=rolli-ng into the-surface thereof at whiteheat a=- finely dividedmetallic substance which contains chromium-a 5. The process of producingan incorrodible article which contains the steps of rolling pulverizedferro chrome mechanically into the surface of a white hot billet offerrousmetal and subsequently continuing the rolling until the desiredshape is obtained and hot billet of ferrous metal, afterwards circlingthe resultant sheet into tubular form and welding the edges togetherlongitudinall V 7 The process of making an incorrodiblc tube whichcontains the steps of heating a steel blank to a temperature ofplasticity, covering the same with a finely divided metallic substance,-which when alloyed produces an impervious adherent, insoluble coatingwhich is infusible at the temperature of such blank, incorporating suchsubstance into said blank by mechanical pressure, expanding such blankinto a sheet by pressure, and afterwards circling said sheet into a tubeand welding the "edges of the sheet to gether.

8. As an article of manufacture a hot rolled ferrous metal sectionhaving a superficial coating of chromium alloy formed thereon in situ.

9. A noncorrodible tube made of hot rolled ferrous metal having itsinner surface coated with an unbroken abherent superficial alloycontaining iron and chromium.

"Intestimony whereof, I hereunto aflix my signature, GEORGE D. BRECK.

